This invention relates to space lattice structures, such as those used currently for flat and curved platforms, for large-span beams, scaffolding, coverings for industrial plants and sports complexes, etc.
It is known that such lattice structures have been heretofore constructed in various ways, nearly always using tubular rods of constant cross-section, which converge in various numbers into knots which are usually of cubic or substantially spherical shape, and in any case closed. However, such systems have certain drawbacks, among which is that the knots or junctions are formed as closed geometrical solids provided with threaded bores into which the ends of the tubular rods are screwed, whereby the assembly has a certain rigidity with little facility for adjusting the lengths, and difficulty in dismantling. However, the most serious drawback is due to the fact that as the tubular rods are of constant cross-section, and as they have to be threaded at their ends for connection to the knot, there is a clear reduction in the resistant cross-section by virtue of the removal of material due to the threading, with consequent reduction in the mechanical strength at the point of connection with the knot, which is a zone of weakness for the whole structure, unless the rod thickness is overdimensioned, with considerable additional costs.
It has been sought to solve this problem by using tubular rods with tapered ends, these ends being substantially frusto-conical elements welded to said rods and each incorporating a bolt for screwing into the threaded bores provided in the knots. However, although this solution overcomes the aforesaid drawbacks fairly well, it is of rather costly and critical construction because of the welding and of the incorporated bolt, and also does not allow inspection of the junctions, which are again of closed type, unless the structure is dismantled.